As X-rays interact with matter in a sample of interest, they alter both the flux of energy in the X-ray wave-field (called the "intensity"), and the direction of energy propagation (called the "phase"). Both the intensity and the phase of the X-rays can provide information about the sample: changes in the X-ray flux are most useful for indicating the presence (or absence) of dense materials such as bone. Meanwhile, changes in the X-ray phase are most useful for examining the lighter elements, such as Carbon and Oxygen, that make up the majority of soft biological structures.
An ideal X-ray microscope would be to measure both the intensity and phase of X-rays, and thus obtain complete knowledge of the X-way wave-field. Unfortunately, this remains difficult. The X-ray phase cannot be directly measured, and must be inferred from other measurements.
In this project the student will explore a cutting-edge "speckle tracking" method for measuring X-ray phase, in which computational image analysis is used to infer the X-ray phase from deformations in a known speckle pattern. This will include writing image analysis software, and performing pilot experiments to test the practicality of this method at the ANU CTLab.